1. Field of the Invention
This invention relates to a soft, nonwoven, fibrous coverstock and a method for manufacturing it.
2. Description of the Related Art
Soft coverstocks are used for finished sanitary products such as a diaper top sheet. In such applications, one face or side of the coverstock material is in contact with a human body (for example, the baby side). It is desirable that this face exhibit softness.
Keen competition for such a product generates a need for reducing the cost of the material. A reduction in basis weight of material has a significant impact on reducing the cost of the material. As basis weight decreases, however, other physical properties of the material or fabric are affected. For example, as basis weight decreases the amount of stretch increases at a given tension; such an increase in stretch in the fabric adversely affects the finished product manufacturer's convertibility.
The magnitude and variability of stretch in the fabric creates convertibility problems. These convertibility problems are exhibited both in the machine direction (MD) and in the cross direction (CD). The stretch characteristics of the fabric in the machine direction contribute to an undesirable wrinkling in the finished product, make verification of the lineal yards on the roll difficult, and create discrepancies between reported yards and yardage measurements by the finished product manufacturer. The stretch characteristics of the fabric in the cross direction also contribute to wrinkling in the finished product, affect component alignment, and require rolls to be slit at greater widths (for example, 131/8 inches for a 121/2 inch diaper), thereby increasing the finished product manufacturer's cost.
Increasing the strength of the fabric may reduce stretch, but usually will also adversely affect softness.